Data transmission method, network device, and terminal device

ABSTRACT

Embodiments of this application provide a data transmission method, a network device, and a terminal device. The method may include detecting, by a network device, a first signal in an uplink signal. The method may also include determining, by the network device, a signal structure of the uplink signal based on a result of detecting the first signal. Furthermore, the method may include receiving, by the network device, the uplink signal based on the signal structure, and/or responding to the uplink signal based on the signal structure. According to the data transmission method in the embodiments of this application, before receiving data, the network device can determine the signal structure, used by the terminal device, of the uplink signal, and then use a corresponding receiving method to avoid complexity and a reliability risk that are caused by completely blind detection performed by the network device, as well as to effectively reduce a delay and signaling overheads.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2017/118913, filed on Dec. 27, 2017, which claims priority toChinese Patent Application No. 201710008469.3, filed on Jan. 5, 2017.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of this application relate to the communications field, andmore specifically, to a data transmission method, a network device, anda terminal device.

BACKGROUND

A request and dynamic grant-based method is usually used to transmituplink data in a long term evolution (LTE) system. Specifically, when adata packet needs to be sent, a terminal device sends a schedulingrequest to a base station, to request, from the base station, a resourceused for sending an uplink data packet, a modulation and coding scheme(MCS) for use, and the like. After receiving the scheduling request, ifthe base station allows the terminal device to send the uplink datapacket, the base station generates grant information and sends the grantinformation to the terminal device, where the grant information is usedto inform the terminal device of information such as the resource usedfor sending the data packet. After receiving the grant information, theterminal device sends the data packet based on an indication of thegrant information.

However, with regard to sending of a small data packet, for example,small-packet services in a massive machine type communications (mMTC)scenario and an enhanced mobile broadband (eMBB) scenario that are in a5G system, delay and signaling overheads are excessively large when therequest and dynamic grant-based data transmission method is used,reducing system efficiency.

To resolve the foregoing problem, a grant-free transmission method isused by some systems for a scenario of small packet transmission withobvious periodicity. Specifically, the base station sends grantinformation to the terminal device only once. In a subsequent uplinktransmission opportunity (such as a subframe), when there is a datapacket, the terminal device sends the data packet by using the grantinformation. In this way, control signaling overheads can besignificantly reduced.

However, when the terminal device transmits uplink data by using thegrant-free transmission method, the terminal device and the base stationneed to be in an uplink synchronized state. To be specific, when theterminal device is in an idle mode or loses uplink synchronization,before transmitting data by using the grant-free transmission method,the terminal device first needs to implement uplink synchronization withthe base station through a random access procedure, and then theterminal device can send the uplink data by using the grant-freetransmission method. Consequently, a delay and signaling overheads arestill relatively large.

SUMMARY

Embodiments of this application provide a data transmission method, anetwork device, and a terminal device, to reduce delay and signalingoverheads.

According to a first aspect, an information transmission method isprovided, including:

detecting, by a network device, a first signal in an uplink signal;

determining, by the network device, a signal structure of the uplinksignal based on a result of detecting the first signal; and

receiving, by the network device, the uplink signal based on the signalstructure, and/or responding to the uplink signal based on the signalstructure.

In this embodiment of this application, before demodulating data, thenetwork device can determine the signal structure, used by a terminaldevice, of the uplink signal, and then use a corresponding receivingmethod. This avoids complexity and a reliability risk that are caused bycompletely blind detection performed by the network device, and caneffectively reduce delay and signaling overheads.

Further, in some possible embodiments, if the network device finds thefirst signal,

the determining, by the network device, a signal structure of the uplinksignal based on a result of detecting the first signal includes:

determining, by the network device, the signal structure based on firstmapping relationship information and the first signal, where the firstmapping relationship information includes: a correspondence between thefirst signal and the signal structure, and/or a correspondence between aresource used for transmitting the first signal and the signalstructure.

In some possible embodiments, the determining, by the network device,the signal structure based on first mapping relationship information andthe first signal includes:

determining, by the network device based on the first mappingrelationship information and the first signal, that the uplink signalincludes only the first signal; and

the receiving, by the network device, the uplink signal based on thesignal structure, and/or responding to the uplink signal based on thesignal structure includes:

sending, by the network device, a response message to a terminal device,where the response message includes feedback information of the firstsignal.

Further, in some possible embodiments, before the receiving, by thenetwork device, the uplink signal based on the signal structure, and/orresponding to the uplink signal based on the signal structure, themethod further includes:

determining, by the network device, a second signal based on secondmapping relationship information and the first signal, where the secondmapping relationship information includes:

a correspondence between the second signal and the first signal, and acorrespondence between the first signal and at least one of a thirdsignal, attribute information of first data, and attribute informationof second data.

In this embodiment of this application, the network device can determinethe second signal, and/or the third signal, and/or the second data basedon a mapping relationship, and receive the first data and/or the seconddata by using the second signal and/or the third signal. This furtherreduces complexity for the network device, reduces a delay, and improvesreliability.

Further, in some possible embodiments, the determining, by the networkdevice, the signal structure based on first mapping relationshipinformation and the first signal includes:

determining, by the network device based on the first mappingrelationship information, the second mapping relationship information,and the first signal, that the uplink signal includes:

the first signal, the second signal, the third signal, and the firstdata; and

the receiving, by the network device, the uplink signal based on thesignal structure, and/or responding to the uplink signal based on thesignal structure includes:

determining, by the network device, the third signal and the attributeinformation of the first data based on the second mapping relationshipinformation and the first signal; receiving, by the network device, thefirst data based on the second signal, the third signal, and theattribute information of the first data; and sending, by the networkdevice, a response message to a terminal device, where the responsemessage includes feedback information of the first signal and feedbackinformation of the first data.

Further, in some possible embodiments, the determining, by the networkdevice, the signal structure based on first mapping relationshipinformation and the first signal includes:

determining, by the network device based on the first mappingrelationship information and the first signal, that the uplink signalincludes:

the first signal, the second signal, and the second data; and

the receiving, by the network device, the uplink signal based on thesignal structure, and/or responding to the uplink signal based on thesignal structure includes:

receiving, by the network device, the second data based on the secondsignal; and sending, by the network device, a response message to aterminal device, where the response message includes feedbackinformation of the first signal.

In some possible embodiments, if the network device finds no firstsignal,

the determining, by the network device, a signal structure of the uplinksignal based on a result of detecting the first signal includes:

determining, by the network device, that the uplink signal includes:

a second signal, a third signal, and first data; and

the receiving, by the network device, the uplink signal based on thesignal structure, and/or responding to the uplink signal based on thesignal structure includes:

determining, by the network device, the second signal and the thirdsignal based on third mapping relationship information; receiving, bythe network device, the first data based on the second signal and thethird signal; and sending, by the network device, a response message toa terminal device, where the response message includes feedbackinformation of the first data.

In this embodiment of this application, the network device can determinethe second signal based on the third mapping relationship information,and receive the second data by using the second signal. This furtherreduces complexity for the network device, reduces a delay, and improvesreliability.

According to a second aspect, a data transmission method is provided,including:

determining, by a terminal device, a signal structure of an uplinksignal based on an uplink status and a type of target data; and

sending, by the terminal device, the uplink signal based on firstmapping relationship information and the signal structure of the uplinksignal.

According to the data transmission method in this embodiment of thisapplication, when the terminal device is to transmit data, the terminaldevice can determine the signal structure of the uplink signal based onthe type of the data and the synchronization status, and transmit theuplink data based on the structure of the uplink transmission signal.This can effectively reduce a delay and signaling overheads.

In some possible embodiments, the uplink status is an uplinkout-of-synchronization state.

Further, in some possible embodiments, the target data is empty; and

the determining, by a terminal device, a signal structure of an uplinksignal based on an uplink status and a type of target data includes:

determining, by the terminal device based on the first mappingrelationship information, that the uplink signal includes only the firstsignal.

Further, in some possible embodiments, before the sending, by theterminal device, the uplink signal based on first mapping relationshipinformation and the signal structure of the uplink signal, the methodfurther includes:

determining, by the terminal device, a second signal based on secondmapping relationship information and the first signal, where

the second mapping relationship information includes:

a correspondence between the second signal and the first signal, and acorrespondence between the first signal and at least one of a thirdsignal, attribute information of first data, and attribute informationof second data.

Further, in some possible embodiments, the target data isapplication-layer data; and

the determining, by a terminal device, a signal structure of an uplinksignal based on an uplink status and a type of target data includes:

determining, by the terminal device based on the first mappingrelationship information and the second mapping relationshipinformation, that the uplink signal includes:

the first signal, the second signal, the third signal, and the firstdata.

Further, in some possible embodiments, the target data isnon-application-layer data; and

the determining, by a terminal device, a signal structure of an uplinksignal based on an uplink status and a type of target data includes:

determining, by the terminal device based on the first mappingrelationship information and the second mapping relationshipinformation, that the uplink signal includes:

the first signal, the second signal, and the second data.

In some possible embodiments, the uplink status is an uplinksynchronized state, and the target data is application-layer data; and

the determining, by a terminal device, a signal structure of an uplinksignal based on an uplink status and a type of target data includes:

determining, by the terminal device based on third mapping relationshipinformation, that the uplink signal includes:

a second signal, a third signal, and first data.

According to a third aspect, a network device is provided, including:

a detection unit, configured to detect a first signal in an uplinksignal;

a processing unit, configured to determine a signal structure of theuplink signal based on a result of detecting the first signal; and

a transceiver unit, configured to receive the uplink signal based on thesignal structure, and/or respond to the uplink signal based on thesignal structure.

The network device in the third aspect can implement the datatransmission method performed by the network device in the method in thefirst aspect.

According to a fourth aspect, a network device is provided, including:

a processor, configured to: detect a first signal in an uplink signal,and determine a signal structure of the uplink signal based on a resultof detecting the first signal; and

a transceiver, configured to receive the uplink signal based on thesignal structure, and/or respond to the uplink signal based on thesignal structure.

The network device in the fourth aspect can implement the datatransmission method performed by the network device in the method in thefirst aspect.

According to a fifth aspect, a terminal device is provided, including:

a processing unit, configured to determine a signal structure of anuplink signal based on an uplink status and a type of target data; and

a transceiver unit, configured to send the uplink signal based on firstmapping relationship information and the signal structure of the uplinksignal.

The terminal device in the fifth aspect can implement the datatransmission method performed by the terminal device in the method inthe second aspect.

According to a sixth aspect, a terminal device is provided, including:

a processor, configured to determine a signal structure of an uplinksignal based on an uplink status and a type of target data; and

a transceiver, configured to send the uplink signal based on firstmapping relationship information and the signal structure of the uplinksignal.

The terminal device in the sixth aspect can implement the datatransmission method performed by the terminal device in the method inthe second aspect.

With reference to the foregoing aspects, in some possible embodiments,the third mapping relationship information includes a correspondencebetween the attribute information of the first data, the second signal,and the third signal.

With reference to the foregoing aspects, in some possible embodiments,the third mapping relationship information includes the correspondencebetween the attribute information of the first data, the second signal,and the third signal.

With reference to the foregoing aspects, in some possible designs, theattribute information includes:

at least one of a cyclic prefix length of an orthogonal frequencydivision multiplexing (OFDM) symbol, an OFDM symbol resource, and amodulation and coding scheme (MCS).

With reference to the foregoing aspects, in some possible embodiments,the first signal is used for uplink synchronization between the terminaldevice and the network device, and the third signal is used to estimatean uplink channel between the terminal device and the network device.

With reference to the foregoing aspects, in some possible embodiments,the response message further includes feedback information of the seconddata.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of an example of a scenario according toan embodiment of this application;

FIG. 2 is a schematic block diagram of a time-frequency resourcelocation according to an embodiment of this application;

FIG. 3 is a schematic block diagram of indicating a signal structure ofan uplink signal by using a first signal according to an embodiment ofthis application;

FIG. 4 is a schematic block diagram of indicating a signal structure ofan uplink signal by using a resource used for transmitting a firstsignal according to an embodiment of this application;

FIG. 5 is a schematic block diagram of indicating a signal structure ofan uplink signal by using a first signal and a resource used fortransmitting the first signal according to an embodiment of thisapplication;

FIG. 6 is a schematic block diagram of a network device for datatransmission according to an embodiment of this application;

FIG. 7 is another schematic block diagram of a network device for datatransmission according to an embodiment of this application;

FIG. 8 is a schematic block diagram of a terminal device for datatransmission according to an embodiment of this application; and

FIG. 9 is another schematic block diagram of a terminal device for datatransmission according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

Random access is a necessary process for establishing a radio linkbetween user equipment (UE) and a network. Only after the UE implementsuplink synchronization with a base station (NodeB, NB) through therandom access procedure can the UE be scheduled by the base station totransmit uplink data.

At present, based on different service triggering manners, random accessmay be classified into contention based random access and non-contentionbased random access.

When the NodeB does not know a service or a state of the UE, but the UEneeds to apply for an uplink resource or an uplink timing advance (TA)for synchronization, the UE needs to initiate contention based randomaccess. An example of a contention based random access procedure is: TheUE sends, to the NodeB, a random access preamble sequence that israndomly selected; the NodeB sends a random access response message tothe UE, to inform the UE of information about an uplink resource thatcan be used; after receiving the random access response, the UE sends ascheduling message on the uplink resource specified in the random accessresponse message, where the scheduling message includes informationabout a unique identifier of the UE; and after receiving a request, theNodeB sends a contention resolution result to the UE, to complete therandom access procedure.

For example, the UE performs initial access. In this case, a state of aradio resource control (RRC) layer is a radio resource control idle(RRC_IDLE) mode. For another example, the UE performs reestablishmentwhen a radio link is torn down. For still another example, the UE is tosend uplink data, but it is found that uplink synchronization is lost orthere is no uplink scheduling request (SR) resource. For yet anotherexample, the UE needs to receive new downlink data, and then transmitacknowledgement/negative acknowledgement (ACK/NACK) information over anuplink, but finds that uplink synchronization is lost. In this case,because the NodeB does not know a service or a state of the UE, the UEneeds to initiate contention based random access.

In non-contention based random access, the NodeB informs the UE of apreamble sequence and a resource that are to be used. An example ofnon-contention based random access procedure is: The NodeB sendsindication information of a random access preamble sequence to the UE;the UE sends the specified random access preamble sequence to the NodeB;and the NodeB sends a random access response to the UE, to complete therandom access procedure.

For example, the UE needs to perform a cell handover. For anotherexample, downlink synchronization is lost, but there is downlink data tobe sent.

It should be noted that, when the terminal device transmits uplink databy using a grant-free transmission method, the terminal device and theNodeB need to be in an uplink synchronized state. In other words, whenthe terminal device transmits the uplink data by using the grant-freetransmission method, the terminal device first needs to perform uplinksynchronization with the NodeB through the random access procedure.Specifically, if the non-contention based random access method is used,the data can be sent only after the three-step random access procedureis performed; or if the contention based random access method is used,the data can be sent only after the four-step random access procedure isperformed. Consequently, delay and signaling overheads are excessivelyhigh.

Embodiments of this application provide a data transmission method. Arandom access procedure and a data transmission process (grant-freetransmission or request and dynamic grant-based transmission) areintegrated, so that based on a synchronization status, a data sendingrequirement (whether data needs to be sent), and information such as achannel status, a terminal can select a proper signal structure from aplurality of uplink sending signal structures for sending.

It should be understood that technical solutions in the embodiments ofthis application can be applied to various communications systems, forexample, a global system for mobile communications (GSM) system, a codedivision multiple access (CDMA) system, a wideband code divisionmultiple access (WCDMA) system, a general packet radio service (GPRS)system, a 5G communications system, an LTE frequency division duplex(FDD) system, an LTE time division duplex (TDD) system, and a universalmobile telecommunications system (UMTS).

In this application, the embodiments are described with reference to anetwork device and a terminal device. The terminal device includes butis not limited to user equipment (UE), an access terminal, a subscriberunit, a subscriber station, a mobile station, a mobile console, a remotestation, a remote terminal, a mobile device, a user terminal, aterminal, a wireless communications device, a user agent, or a userapparatus. The terminal device may communicate with one or more corenetworks by using a radio access network (RAN). For example, theterminal device may be a cellular phone, a cordless telephone set, asession initiation protocol (SIP) phone, a wireless local loop (WLL)station, a personal digital assistant (PDA), a handheld device having awireless communication function, a computing device, another processingdevice connected to a wireless modem, an in-vehicle device, a wearabledevice, a terminal device in a future 5G network, or a terminal devicein a future evolved PLMN network.

The network device may be a device configured to communicate with theterminal device, and the network device may include a base station or anetwork side device having a function of a base station. For example,the network device may be a base transceiver station (BTS) in the GSMsystem or the CDMA system; a NodeB (NB) in the WCDMA system; an evolvedNodeB (eNB or eNodeB), a relay node, or an access point in the LTEsystem; an in-vehicle device or a wearable device; or a network devicein a future 5G network.

The following describes the technical solutions in the embodiments ofthis application with reference to the accompanying drawings.

FIG. 1 is a schematic flowchart of a data transmission method 100according to an embodiment of this application. As shown in FIG. 1, themethod 100 includes the following steps.

S110. A terminal device determines a signal structure of an uplinksignal based on an uplink status of the terminal device and a type oftarget data.

Specifically, in embodiments, the terminal device may select differentsignal structures for uplink data transmission, based on asynchronization status of the terminal device and a specific type ofdata that needs to be sent. The synchronization status of the firstterminal may be an uplink out-of-synchronization state or an uplinksynchronized state.

In other words, when receiving the uplink data, a network device detectsand receives the uplink data based on the signal structure of the uplinksignal, and sends feedback information of the data.

It should be understood that the signal structure of the uplink signalin this embodiment of this application may be used to indicate a type ofthe signal included in the uplink data. To be specific, when theterminal device needs to send the data or feedback information of datato the network device, the terminal device may send the uplink databased on the determined signal structure of the uplink signal; and thenetwork device determines the specific type of the signal in the uplinkdata of the terminal device based on the signal structure of the uplinksignal.

It should also be understood that the uplink status in this embodimentof this application may be classified into an uplink synchronized stateand an uplink out-of-synchronization state. Specific representationforms of the uplink synchronized state and the uplinkout-of-synchronization state are not limited in this embodiment of thisapplication. For example, the uplink out-of-synchronization state maymean that the terminal device is in an idle mode (which means that thereis no Radio Resource Control connection and uplink synchronization withthe base station is not implemented); or may mean that the terminaldevice is in a connected mode and has a Radio Resource Controlconnection, but loses uplink synchronization with the base station.

For ease of understanding, the following uses examples to classify anddescribe signals and data in uplink transmission performed by theterminal device in this embodiment of this application.

A first signal is a sequence or a signal that is used to implementuplink synchronization between the terminal device and the networkdevice, for example, a random access preamble sequence in the LTEsystem. Based on a detection status of the signal, the network devicemay determine a synchronization parameter of the terminal, for example,a timing advance (TA).

A second signal is used by the network device when receiving data, todetermine the terminal device corresponding to the data. That is, theterminal detects the signal to determine whether the terminal has sentuplink data. For example, the second signal is an identification signalor a sequence of the terminal device.

A third signal is a sequence used by the network device to estimate anuplink channel between the terminal device and the network device, forexample, a pilot sequence or a demodulation reference signal (DMRS) inLTE. The network device may perform the channel estimation to demodulatedata sent by the terminal.

First data is a payload that can be demodulated and received by thenetwork device only after the network device performs channel estimationby using a third signal, for example, an application-layer data packet,a buffer status report of the terminal, a scheduling request, oridentification (for example, an ID) information of the terminal device.

Second data is a signal or a sequence that can be received by thenetwork device without performing channel estimation by using a thirdsignal, for example, a signal or a sequence used to implement a functionof a scheduling request.

It should be understood that the first signal, the second signal, thethird signal, the first data, and the second data in this embodiment ofthis application may be signals or sequences used to implement theforegoing functions, or may be signals or sequences used to implementother functions. The protection scope of this embodiment of thisapplication covers a logical relationship between the signals and thedata, and specific functions of the signals and the data are not limitedin this embodiment of this application.

It should also be understood that at least two of the first signal, thesecond signal, the third signal, and the second data are a same sequenceor a same signal in this embodiment of this application. In other words,the terminal device may send only one signal or sequence to the networkdevice, to implement functions of at least two of the first signal, thesecond signal, the third signal, and the second data that are describedabove. A quantity of signals and a specific representation form of thesignal are not limited in this embodiment of this application.

For example, the second signal and the third signal may be a same pilotsequence.

According to the data transmission method in this embodiment of thisapplication, when the terminal device is to transmit data, the terminaldevice can determine the signal structure of the uplink signal based onthe type of the data and the synchronization status, and transmit theuplink data based on the structure of the uplink transmission signal.This can effectively reduce a delay and signaling overheads.

The following describes in detail signal structures of uplink signals inthis embodiment of this application by using the first signal, thesecond signal, the third signal, the first data, and the second data asexamples. Specifically, the signal structures may be classified into thefollowing four types.

A signal structure 1 is the first signal, and is used to implement onlyuplink synchronization between the terminal and the network device.

A signal structure 2 includes the first signal, the second signal, thethird signal, and the first data, and is used to implement uplinksynchronization between the terminal and the network device and send thefirst data.

A signal structure 3 includes the first signal, the second signal, andthe second data, and is used to implement uplink synchronization betweenthe terminal and the network device and send the second data.

A signal structure 4 includes the second signal, the third signal, andthe first data, and is used to send the first data.

FIG. 2 is a schematic block diagram of a time-frequency resource usedfor sending a signal and/or data according to an embodiment of thisapplication.

As shown in FIG. 2, in this embodiment of this application,time-frequency resources used for sending signals and/or data may be thesame or may be different; and may be consecutive or inconsecutive intime domain, may be consecutive or inconsecutive in frequency domain, ormay be consecutive or inconsecutive both in time domain and in frequencydomain. B1 and B2 are used to indicate different frequency domainresources, and T1 and T2 are used to indicate different time domainresources.

For example, in the signal structure 1, a time-frequency resource usedfor sending the first signal may be the same as or different from atime-frequency resource used for sending the second signal and/or thethird signal; and may be consecutive or inconsecutive in time domain,may be consecutive or inconsecutive in frequency domain, or may beconsecutive or inconsecutive both in time domain and in frequencydomain.

For another example, in the signal structure 2, a time-frequencyresource used for sending the first signal and a time-frequency resourceused for sending the first data may be consecutive or inconsecutive intime domain, may be consecutive or inconsecutive in frequency domain, ormay be consecutive or inconsecutive both in time domain and in frequencydomain.

For still another example, in the signal structure 3, a time-frequencyresource used for sending the first signal and a time-frequency resourceused for sending the second data may be consecutive or inconsecutive intime domain, may be consecutive or inconsecutive in frequency domain, ormay be consecutive or inconsecutive both in time domain and in frequencydomain.

For yet another example, in the signal structure 4, a time-frequencyresource used for sending the second signal and/or the third signal anda time-frequency resource used for sending the first data may beconsecutive or inconsecutive in time domain, may be consecutive orinconsecutive in frequency domain, or may be consecutive orinconsecutive both in time domain and in frequency domain.

Optionally, in this embodiment of this application, the second signalmay be configured with a time-frequency resource the same as thatconfigured for the first data. That is, the second signal is bound tothe time-frequency resource for the first data, to be sent on thetime-frequency resource for the first data. It should be understoodthat, alternatively, the second signal in this embodiment of thisapplication may be bound to a time-frequency resource for another signalor other data, for example, the third signal, the first signal, or thesecond data, to be sent on the time-frequency resource for the anothersignal or other data.

In S110, the terminal device may determine the specific uplinktransmission signal structure based on the synchronization status andthe type of the data.

For example, if the terminal device is in the out-of-synchronizationstate and the type of the data is the first data, the structure of theuplink transmission signal may be the signal structure 1 or the signalstructure 2.

For another example, if the terminal device is in theout-of-synchronization state and the type of the data is the seconddata, the structure of the uplink transmission signal may be the signalstructure 1 or the signal structure 3.

For still another example, if the terminal device is in the synchronizedstate and the type of the data is the first data, the structure of theuplink transmission signal may be the signal structure 4.

For yet another example, if the terminal device is in the synchronizedstate and the type of the data is not the first data, no signalstructure is sent.

Optionally, the terminal device may determine the synchronization statusbased on whether a timer times out, or the network device may inform theterminal device that a synchronization parameter needs to be obtainedanew. This is not specifically limited in this embodiment of thisapplication.

With reference to S120, S130, and S140 in the method embodiment 100, thefollowing describes in detail embodiments of a specific implementationof uplink transmission between the terminal device and the networkdevice for the foregoing four signal structures.

S120. The terminal device sends the uplink signal to a network device.

S130. The network device detects a first signal in the uplink signal.

S140. The network device receives the uplink signal based on a result ofdetecting the first signal, and/or responds to the uplink signal basedon the result of detecting the first signal.

In an embodiment, if the terminal device determines that the signalstructure of the uplink signal is the signal structure 1, the terminaldevice only needs to perform uplink synchronization.

Specifically, the terminal device determines, based on first mappingrelationship information and the signal structure 1, a first signalcorresponding to the signal structure 1 from a plurality of signals usedfor implementing a function of the first signal, and sends the firstsignal to the network device, that is, the uplink data sent by theterminal device includes only the first signal. In other words, afterthe network device receives the first signal, the first signal may beused to implicitly inform the network device of a specific uplinktransmission signal structure corresponding to the first signal.

The network device may determine, based on the detected first signal andthe first mapping relationship, that the signal structure, of the uplinksignal, corresponding to the first signal is the signal structure 1,that is, the uplink data includes only the first signal. In this case,the network device determines a synchronization parameter based on thefirst signal sent by the terminal device, and sends response informationto the terminal device, where the response information includes thesynchronization parameter.

Optionally, the response information further includes grant information,for example, a time-frequency resource and a modulation and codingscheme, that is to be used by the terminal device for next transmission.

It should be noted that, when finding the first signal, the networkdevice actually does not need to know a specific terminal sending thefirst signal. The network device only needs to determine, based on thefound first signal, a TA corresponding to the first signal, and thendeliver the TA. Delivered content includes two parts: information (suchas an index) that can identify the found first signal, and the TAcorresponding to the first signal. The terminal side may actuallyreceive a plurality of TAs, where each TA is corresponding to one firstsignal. The terminal only needs to find the TA corresponding to thefirst signal sent by the terminal.

In this embodiment of this application, to avoid a conflict of firstsignals between terminal devices, the network device optionallyconfigures one first signal for each terminal device.

Optionally, the first mapping relationship information includes acorrespondence between the first signal and the signal structure of theuplink signal, and/or a correspondence between a resource used fortransmitting the first signal and the signal structure of the uplinksignal.

The following describes in detail the first mapping relationship in thisembodiment of this application with reference to FIGS. 3-5.

In an embodiment, the terminal device implicitly indicates the signalstructure of the uplink signal by using the first signal.

Specifically, in an embodiment, the network device classifies sequencesused to implement the function of the first signal into at least threetypes: a first type, a second type, and a third type. Each type includesat least one sequence. The network device establishes, in advance, amapping relationship between the types obtained through classificationand a signal structure.

FIG. 3 shows a mapping relationship between a first signal and astructure of an uplink transmission signal according to an embodiment ofthis application.

Specifically, as shown in FIG. 3, a first signal 1 in a first type iscorresponding to a signal structure 1, a first signal 2 in a second typeis corresponding to a signal structure 2, a first signal 3 in a thirdtype is corresponding to a signal structure 3, and a signal structure 4is used when there is no first signal.

To be specific, if the terminal device selects the signal structure 1,the terminal device determines, based on the signal structure 1, that acorresponding type is the first type; selects, as a first signal, onesequence from a sequence in the first type according to a rule, forexample, in a random selection manner or another manner; and sends thefirst signal to the network device. The network device detects the firstsignal. If finding that the sequence belongs to the first type, thenetwork device may determine, based on a predefined mappingrelationship, that a signal structure of an uplink signal of theterminal device is the signal structure 1. In other words, only thefirst signal is included.

In an embodiment, the terminal device implicitly indicates the signalstructure of the uplink signal by using a first resource used fortransmitting the first signal.

Specifically, the terminal device implicitly indicates the signalstructure of the uplink signal by mapping selected first signals todifferent time-frequency resources. Optionally, the network deviceclassifies locations of time-frequency resources used for sending firstsignals, and establishes a correspondence between a time-frequencyresource location and a signal structure. For example, the networkdevice classifies the locations of time-frequency resources used forsending the first signals into at least three types: a first type, asecond type, and a third type, where the three types of locations oftime-frequency resources partially overlap or do not overlap at all; andestablishes a mapping relationship between the types obtained throughclassification and a signal structure.

FIG. 4 shows a mapping relationship between a resource used fortransmitting a first signal and a structure of an uplink transmissionsignal according to an embodiment of this application.

Specifically, as shown in FIG. 4, a time-frequency resource 1, used fortransmitting a first signal 1, in a first type is corresponding to asignal structure 1; a time-frequency resource 2, used for transmitting afirst signal 1, in a second type is corresponding to a signal structure2; and a time-frequency resource 3, used for transmitting a first signal1, in a third type is corresponding to a signal structure 3.

To be specific, if selecting to send the signal structure 1, the firstterminal sends the first signal at a first-type time-frequency resourcelocation. The network device detects, at a possible time-frequencyresource location, the first signal sent by the terminal device. Iffinding that the terminal device sends the first signal on a first-typetime-frequency resource, the network device may determine, based on thepredefined mapping relationship, that a signal structure of an uplinksignal of the terminal device is the signal structure 1. In other words,only the first signal is included.

It should be understood that in this embodiment of this application, theterminal device may classify first signals into three types which areused to indicate the signal structure 1, the signal structure 2, and thesignal structure 3 respectively; or may establish a one-to-onecorrespondence between a first signal and a signal structure of anuplink signal. This is not specifically limited in this embodiment ofthis application.

In an embodiment, as shown in FIG. 5, the terminal device mayalternatively indicate a signal structure of an uplink signal by using afirst signal and a resource used for transmitting the first signal.

Specifically, as shown in FIG. 5, a time-frequency resource 1 used fortransmitting a first signal 1 is corresponding to a signal structure 1;a time-frequency resource 2 used for transmitting a first signal 1 iscorresponding to a signal structure 2; and a time-frequency resource 2used for transmitting a first signal 2 is corresponding to a signalstructure 3.

According to the data transmission method in this embodiment of thisapplication, before demodulating data, the network device can determinethe signal structure, used by the terminal device, of the uplink signal,and then use a corresponding receiving method. This resolves a problemof a low delay and excessively high signaling overheads in an eMBBsmall-packet scenario, an mMTC scenario, and a URLLC scenario.

In another embodiment, if the terminal device determines that the signalstructure of the uplink signal is the signal structure 2, the terminaldevice needs to perform uplink synchronization and send the first data.

Specifically, the terminal device determines, based on the first mappingrelationship information and the signal structure 2, the first signalcorresponding to the signal structure 2; determines the second signaland the third signal based on a second mapping relationship and thefirst signal; and sends uplink data to the network device, where theuplink data includes the first signal, the second signal, the thirdsignal, and the first data.

To be specific, after finding the first signal, the network device candetermine, based on the first signal and the first mapping relationshipinformation, that the signal structure, of the uplink signal,corresponding to the first signal is the signal structure 2, that is,determine that the uplink data corresponding to the first signalspecifically includes the first signal, the second signal, the thirdsignal, and the first data. In this case, the network device determines,based on the second mapping relationship information and the firstsignal, the second signal and the third signal that are corresponding tothe first signal, and demodulates and receives the first data based onthe second signal and the third signal.

The network device determines a synchronization parameter based on thefirst signal, and sends response information to the terminal device. Theresponse information includes the synchronization parameter and feedbackinformation of a result of receiving the first data, for example,information indicating that the first data is correctly received orincorrectly received. Optionally, the response information furtherincludes grant information, for example, a time-frequency resource and amodulation and coding scheme, that is to be used by the terminal devicefor next transmission.

Optionally, the second mapping relationship information includes acorrespondence between the second signal and the first signal, and acorrespondence between the first signal and at least one of the thirdsignal, attribute information of the first data, and attributeinformation of the second data, where the second signal is used toidentify the terminal device.

Optionally, the attribute information may include at least one of acyclic prefix length of an orthogonal frequency division multiplexingOFDM symbol, an OFDM symbol resource, and a modulation and coding schemeMCS.

It should be understood that the attribute information in thisembodiment of this application may be alternatively power for sending asignal/data, for example, power for the second data or power for secondinformation. This is not specifically limited in this embodiment of thisapplication.

In this embodiment of this application, to ensure receiving of a signaland data in the out-of-synchronization state, optionally, a relativelylong cyclic prefix may be used for sending the second signal, the thirdsignal, the second data, and/or the first data.

In this embodiment of this application, after receiving data, thenetwork device needs to know a terminal sending the data. The secondmapping relationship may be established to determine the second signaland/or the third signal in this embodiment of this application. However,this is not limited in this embodiment of this application.

For example, the terminal device may package identification information,such as a unique identifier of the terminal device, into data, and sendthe identification information as a part of the data to the networkdevice. In this way, after correctly receives the data, the networkdevice can know the terminal device from which the data comes.

In this embodiment of this application, the network device can determinethe second signal and the third signal based on the second mappingrelationship information, and receive the first data by using the secondsignal and the third signal. This effectively reduces complexity for thenetwork device, reduces a delay, and improves reliability.

In another embodiment, if the terminal device determines that the signalstructure of the uplink signal is the signal structure 3, that is, ifthe terminal device is in the uplink out-of-synchronization state, theterminal device only needs to send the second data to the networkdevice.

Specifically, the terminal device determines, based on the first mappingrelationship information and the signal structure 3, the first signalcorresponding to the signal structure 3; determines the second signalbased on the second mapping relationship and the first signal; and sendsuplink data to the network device, where the uplink data includes thefirst signal, the second signal, and the second data.

To be specific, after finding the first signal, the network device candetermine, based on the first signal and the first mapping relationshipinformation, that the signal structure, of the uplink signal,corresponding to the first signal is the signal structure 3, that is,determine that the uplink data corresponding to the first signalspecifically includes the first signal, the second signal, and thesecond data. In this case, the network device determines, based on thesecond mapping relationship information and the first signal, the secondsignal corresponding to the first signal, and receives the second databased on the second signal.

The network device determines a synchronization parameter based on thefirst signal, and sends response information to the terminal device,where the response information includes the synchronization parameter.Optionally, the response information further includes grant information,for example, a time-frequency resource and a modulation and codingscheme, that is to be used by the terminal device for next transmission.

Optionally, the response message may further include feedbackinformation of the second data. For example, the second data is ascheduling request sequence or signal, and the response message furtherincludes feedback information of the scheduling request sequence orsignal.

In this embodiment of this application, the network device can determinethe second signal based on the second mapping relationship information,and receive the second data by using the second signal. This effectivelyreduces complexity for the network device, reduces a delay, and improvesreliability.

In another embodiment, if the terminal device determines that the signalstructure of the uplink signal is the signal structure 4, that is, ifthe terminal device is in an uplink connected state, the terminal deviceonly needs to send the first data to the network device.

Specifically, the terminal device determines, based on the first mappingrelationship information and the signal structure 4, that the signalstructure 4 does not include the first signal; determines the secondsignal based on the second mapping relationship and the first signal;and sends uplink data to the network device, where the uplink dataincludes the second signal, the third signal, and the first data.

To be specific, after finding no first signal, the network device candetermine, based on the first signal and the first mapping relationshipinformation, that the signal structure of the uplink signal is thesignal structure 4, that is, determine that the uplink data specificallyincludes the second signal, the third signal, and the second data. Inthis case, the network device determines, based on third mappingrelationship information, the second signal and the third signal, andreceives the first data based on the second signal and the third signal.

The network device sends response information to the terminal device.The response information includes a result of receiving the first data,for example, the first data is correctly received or incorrectlyreceived. Optionally, the response information further includes grantinformation, for example, a time-frequency resource and a modulation andcoding scheme, that is to be used by the terminal device for nexttransmission.

Optionally, the third mapping relationship information includes acorrespondence between attribute information of the first data, thesecond signal, and the third signal.

In this embodiment of this application, the network device can determinethe second signal based on the third mapping relationship information,and receive the second data by using the second signal. This effectivelyreduces complexity for the network device, reduces a delay, and improvesreliability.

In this embodiment of this application, the terminal device candetermine the signal structure of the uplink signal based on the firstsignal and the first mapping relationship information, and there is alsothe second mapping relationship information between the signal in theuplink data and the first signal.

In other words, the network device can determine, based on the detectedfirst signal and the first mapping relationship information, the signalstructure, of the uplink signal, corresponding to the first signal; andcan determine, based on the second mapping relationship information, thesecond signal and/or the third signal used to receive the data.

In this embodiment of this application, the network device candetermine, based on the first mapping relationship information, that thestructure of the uplink transmission signal is the signal structure 4,and receive the first data based on the signal structure 4. Thiseffectively reduces complexity for the network device, reduces a delay,and improves reliability.

It should be noted that according to the data transmission method inthis embodiment of this application, the network device can receive theuplink data without blind detection, so that a processing procedure issimplified. This can effectively improve data processing efficiency andreduce a delay.

Specifically, if the second signal and the second signal are a samepilot sequence, the network device pre-allocates one pilot to eachterminal, and terminal devices are corresponding to different pilots.The network device allocates three preambles (P_i1, P_i2, and P_i3) tothe terminal device, where the three preambles are respectivelycorresponding to the signal structure 1, the signal structure 2, and thesignal structure 3. It is assumed that a quantity of the terminaldevices is N=5. When a signal structure of an uplink signal of aterminal device 1 is the signal structure 1, a signal structure of anuplink signal of a terminal device 2 is the signal structure 2, a signalstructure of an uplink signal of a terminal device 3 is the signalstructure 3, a signal structure of an uplink signal of a terminal device4 is the signal structure 4, and a terminal device 5 does not performsending.

If finding P_11, the network device determines that the signal structureof the uplink signal of the terminal device 1 is the signal structure 1,and no longer detects R_1. If finding P_22, the network devicedetermines that the signal structure of the uplink signal of theterminal device 2 is the signal structure 2, detects R_2 by using a longcyclic prefix, performs channel estimation, and receives the first data.If finding P_33, the network device determines that the signal structureof the uplink signal of the terminal device 3 is the signal structure 3,detects R_3 by using a long cyclic prefix, detects R_4 and R_5 by usinga short cyclic prefix, performs corresponding channel estimation, andreceives the first data.

If no first mapping relationship information is established in thisembodiment of this application, the network device receives data throughblind detection during grant-free transmission. To be specific, thenetwork device needs to first detect, on a time-frequency resource, NTAs by using N preambles, and then attempt to detect N terminal devicesby using N pilot sequences. Moreover, the network device does not knowcyclic prefixes used by the terminal device for sending another signaland other data that are different from the preambles, and consequentlyfails in detection and receiving.

In contrast, according to the data transmission method in thisembodiment of this application, before receiving data, the networkdevice can determine a specific signal structure sent by the terminal,and then use a corresponding receiving method. This avoids complexityand a reliability risk that are caused by completely blind detectionperformed by the base station, and implements transmission with a lowdelay and low signaling overheads in the eMBB small-packet scenario, themMTC scenario, and the URLLC scenario.

Therefore, based on the first mapping relationship information in thisembodiment of this application, the network device can receive theuplink data without blind detection, so that a processing procedure issimplified. This can effectively improve data processing efficiency andreduce a delay.

In this embodiment of this application, before detecting the firstsignal, the network device may send at least one of the first mappingrelationship information, the second mapping relationship information,and the third mapping relationship information to the terminal device.

The following describes a network device and a terminal device in theembodiments of this application with reference to FIG. 6 and FIG. 9.

FIG. 6 is a schematic block diagram of a network device for datatransmission according to an embodiment of this application. As shown inFIG. 6, the network device in this embodiment of this applicationincludes:

a detection unit 210, configured to detect a first signal in an uplinksignal;

a processing unit 220, configured to determine a signal structure of theuplink signal based on a result of detecting the first signal; and

a transceiver unit 230, configured to receive the uplink signal based onthe signal structure, and/or respond to the uplink signal based on thesignal structure.

Optionally, if the network device finds the first signal, the processingunit 220 is specifically configured to determine the signal structure ofthe uplink signal based on first mapping relationship information andthe first signal.

The first mapping relationship information includes a correspondencebetween the first signal and the signal structure, and/or acorrespondence between a resource used for transmitting the first signaland the signal structure.

Optionally, the processing unit 220 is configured to determine, based onthe first mapping relationship information and the first signal, thatthe uplink signal includes only the first signal.

The transceiver unit 230 is configured to send a response message, wherethe response message includes feedback information of the first signal.

Optionally, the processing unit 220 is configured to determine theterminal device based on second mapping relationship information and thefirst signal.

The second mapping relationship information includes a correspondencebetween a second signal and the first signal, and a correspondencebetween the first signal and at least one of a third signal, attributeinformation of first data, and attribute information of second data,where the second signal is used to identify the terminal device.

Optionally, the processing unit 220 is configured to determine, based onthe first mapping relationship information, the second mappingrelationship information, and the first signal, that the uplink signalincludes the first signal, the second signal, the third signal, and thefirst data.

The transceiver unit 230 is configured to: determine the third signaland the attribute information of the first data based on the secondmapping relationship information and the first signal; receive the firstdata based on the second signal, the third signal, and the attributeinformation of the first data; and send a response message to theterminal device, where the response message includes feedbackinformation of the first signal and feedback information of the firstdata.

Optionally, the processing unit 220 is configured to determine, based onthe first mapping relationship information, the second mappingrelationship information, and the first signal, that the uplink signalincludes the first signal, the second signal, and the second data.

The transceiver unit 230 is configured to: receive the second data basedon the second signal; and send a response message, where the responsemessage includes feedback information of the first signal.

Optionally, the processing unit 220 is configured to: if the detectionunit 210 finds no first signal, determine, based on third mappingrelationship information, that the uplink signal includes a secondsignal, a third signal, and first data.

The transceiver unit 230 is configured to: receive the first data basedon the second signal and the third signal, and send a response messageto the terminal device, where the response message includes feedbackinformation of the first data.

Optionally, the third mapping relationship information includes acorrespondence between attribute information of the first data, thesecond signal, and the third signal.

Optionally, the attribute information includes at least one of a cyclicprefix length of an OFDM symbol, an OFDM symbol resource, and amodulation and coding scheme MCS.

Optionally, the response message further includes uplink grantinformation of the terminal device.

Optionally, the first signal is used for uplink synchronization betweenthe terminal device and the network device, the second signal is used toidentify the terminal device, the third signal is used to estimate anuplink channel between the terminal device and the network device, thefirst data is application-layer data, and the second data isnon-application-layer data.

Optionally, at least two of the first signal, the second signal, thethird signal, and the second data are a same sequence or a same signal.

Optionally, before the detection unit 210 detects the first signal, thetransceiver unit 230 is further configured to send at least one of thefirst mapping relationship information, the second mapping relationshipinformation, and the third mapping relationship information to theterminal device.

It should be understood that the network device 200 in this embodimentof this application may correspond to the network device in the methodembodiments of this application. In addition, operations and/orfunctions of the modules and other modules in the network device 200 areintended to implement corresponding procedures of the method 100. Forbrevity, details are not described herein again.

It should be noted that in this embodiment of this application, thedetection unit 210 and the processing unit 220 may be implemented by aprocessor, and the transceiver unit 230 may be implemented by atransceiver. As shown in FIG. 7, a network device 300 may include aprocessor 310, a transceiver 320, and a memory 330. The memory 330 maybe configured to store indication information, and may be furtherconfigured to store code, an instruction, and the like that are to beexecuted by the processor 310 to perform the processes discussed herein.

The components of the network device 300 are connected by using a bussystem. In addition to a data bus, the bus system includes a power bus,a control bus, and a status signal bus.

The network device 300 shown in FIG. 7 or the network device 200 shownin FIG. 6 can implement the processes implemented by the network devicein the method embodiment in FIG. 1. To avoid repetition, details are notdescribed herein again.

FIG. 8 is a schematic block diagram of a terminal device 400 for datatransmission according to an embodiment of this application. As shown inFIG. 8, the terminal device 400 in this embodiment of this applicationincludes:

a processing unit 410, configured to determine a signal structure of anuplink signal based on an uplink status and a type of target data; and

a transceiver unit 420, configured to send the uplink signal based onfirst mapping relationship information and the signal structure of theuplink signal.

Optionally, the first mapping relationship information includes:

a correspondence between a first signal and the signal structure of theuplink signal, and/or a correspondence between a resource used fortransmitting the first signal and the signal structure of the uplinksignal.

Optionally, the uplink status is an uplink out-of-synchronization state.

Optionally, the target data is empty; and the processing unit 410 isconfigured to determine, based on the first mapping relationshipinformation, that the uplink signal includes only the first signal.

Optionally, before the transceiver unit sends the uplink signal based onthe first mapping relationship information and the signal structure ofthe uplink signal, the processing unit 410 is further configured to

determine a second signal based on second mapping relationshipinformation and the first signal, where the second mapping relationshipinformation includes a correspondence between the second signal and thefirst signal, and a correspondence between the first signal and at leastone of a third signal, attribute information of first data, andattribute information of second data, and the second signal is used toidentify the terminal device.

Optionally, the target data is application-layer data; and theprocessing unit 410 is configured to determine, based on the firstmapping relationship information and the second mapping relationshipinformation, that the uplink signal includes the first signal, thesecond signal, the third signal, and the first data.

Optionally, the target data is non-application-layer data; and theprocessing unit 410 is configured to determine, based on the firstmapping relationship information and the second mapping relationshipinformation, that the uplink signal includes the first signal, thesecond signal, and the second data.

Optionally, the uplink status is an uplink synchronized state, and thetarget data is application-layer data; and the processing unit 410 isconfigured to

determine, based on the first mapping relationship information and thethird mapping relationship information, that the uplink signal includesa second signal, a third signal, and first data.

Optionally, the third mapping relationship information includes acorrespondence between attribute information of the first data, thesecond signal, and the third signal.

It should be understood that the terminal device 400 in this embodimentof this application may be corresponding to the terminal device in themethod embodiment of this application. In addition, operations and/orfunctions of the modules and other modules in the terminal device 400are intended to implement corresponding procedures of the method 100.For brevity, details are not described herein again.

It should be noted that in this embodiment of this application, theprocessing unit 410 may be implemented by a processor, and thetransceiver unit 420 may be implemented by a transceiver. As shown inFIG. 9, a terminal device 500 may include a processor 510, a transceiver520, and a memory 530. The memory 530 may be configured to storeindication information, and may be further configured to store code, aninstruction, and the like that are to be executed by the processor 510to perform the processes discussed herein.

The components of the terminal device 500 are connected by using a bussystem. In addition to a data bus, the bus system includes a power bus,a control bus, and a status signal bus.

In embodiments implementing the processes discussed herein, the steps ofthe foregoing methods may be completed using a hardware integrated logiccircuit in the processor, or by using an instruction in a form ofsoftware. The steps of the methods disclosed with reference to theembodiments of this application may be directly performed by a hardwareprocessor, or may be performed by a combination of hardware in theprocessor and a software module. The software module may be located in amature storage medium in the art, such as a random access memory, aflash memory, a read-only memory, a programmable read-only memory, anelectrically erasable programmable memory, or a register. The storagemedium is located in the memory. The processor executes the instructionin the memory, and completes the steps of the foregoing methods incombination with the hardware in the processor. To avoid repetition,details are not described herein again.

The terms used in the embodiments of this application and the appendedclaims are only intended to describe specific embodiments, but are notintended to limit this application.

For example, the term “and/or” in the embodiments of this applicationdescribes only an association relationship for describing associatedobjects and represents that three relationships may exist. Specifically,A and/or B may represent the following three cases: Only A exists, bothA and B exist, and only B exists. In addition, the character “/” in thisspecification generally indicates an “or” relationship betweenassociated objects.

For another example, “a”, “the”, and “the foregoing” in singular formsused in the embodiments of this application and the appended claims areintended to include a plural form, unless other meanings are clearlyindicated in a context.

For still another example, terms such as “first”, “second”, and “third”may be used in the embodiments of this application to describe variousmessages, requests, and terminals, but the messages, requests, andterminals should not be limited to these terms. These terms are onlyused to distinguish between the messages, requests, and terminals. Forexample, a first terminal may also be referred to as a second terminal,and similarly a second terminal may also be referred to as a firstterminal, provided that this does not depart from the scope of theembodiments of this application.

For yet another example, depending on a context, a word “if” used hereinmay be interpreted as “while”, “when”, “in response to determining”, or“in response to detecting”. Similarly, depending on a context, phrases“if determining” or “if detecting (a stated condition or event)” may beinterpreted as “when determining”, “in response to determining”, “whendetecting (the stated condition or event)”, or “in response to detecting(the stated condition or event)”.

A person of ordinary skill in the art may be aware that units andalgorithm steps in the examples described with reference to theembodiments disclosed in this specification can be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraints of thetechnical solutions. A person skilled in the art may use a differentmethod to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of this application.

It may be clearly understood by a person skilled in the art that, for apurpose of ease and brevity of description, for detailed workingprocesses of the foregoing system, apparatus, and unit, reference may bemade to corresponding processes in the foregoing method embodiments.Details are not described herein again.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiments are merely examples. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or may be integrated into another system, or some features maybe ignored or may not be performed. In addition, the displayed ordiscussed mutual couplings or direct couplings or communicationconnections may be implemented through some interfaces. The indirectcouplings or communication connections between the apparatuses or unitsmay be implemented in electrical, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected depending on anactual requirement, to achieve the objectives of the embodiments of thisapplication.

In addition, functional units in the embodiments of this application maybe integrated into one processing unit, or each of the units may existalone physically, or at least two units may be integrated into one unit.

When the functions are implemented in a form of a software functionalunit and sold or used as an independent product, the functions may bestored in a computer-readable storage medium. Based on such anunderstanding, the technical solutions of this application essentially,or the part contributing to the prior art, or some of the technicalsolutions may be implemented in a form of a software product. Thecomputer software product is stored in a storage medium, and includesseveral instructions for instructing a computer device (which may be apersonal computer, a server, a network device, or the like) to performall or some of the steps of the methods described in the embodiments ofthis application. The foregoing storage medium includes any medium thatcan store program code, such as a USB flash drive, a removable harddisk, a read-only memory (ROM), a random access memory (RAM), a magneticdisk, or an optical disc.

The foregoing content is merely specific implementations of thisapplication, but is not intended to limit the protection scope of thisapplication. Any variation or replacement readily figured out by aperson skilled in the art within the technical scope disclosed in thisapplication shall fall within the protection scope of this application.Therefore, the protection scope of this application shall be subject tothe protection scope of the claims.

What is claimed is:
 1. A data transmission method, comprising:determining, by a terminal device, a signal structure of an uplinksignal based on an uplink status and a type of target data; and sending,by the terminal device, a selected first signal using the signalstructure of the uplink signal based on first mapping relationshipinformation and the signal structure of the uplink signal, the selectedfirst signal sent to a network device using a selected one of aplurality of different time-frequency resources, and the first mappingrelationship information indicating to the network device the signalstructure of the uplink signal based on a mapping between the selectedfirst signal to the selected time-frequency resource.
 2. The methodaccording to claim 1, wherein the first mapping relationship informationcomprises: a correspondence between the first signal and the signalstructure, and/or a correspondence between a resource used fortransmitting the first signal and the signal structure.
 3. The methodaccording to claim 1, wherein the uplink status is an uplinkout-of-synchronization state.
 4. The method according to claim 3,wherein the target data is empty, and wherein the determining, by theterminal device, the signal structure of the uplink signal based on theuplink status and the type of target data further comprises:determining, by the terminal device based on the first mappingrelationship information, that the uplink signal comprises only thefirst signal.
 5. The method according to claim 1, wherein before thesending, by the terminal device, the uplink signal based on firstmapping relationship information and the signal structure of the uplinksignal, the method further comprises: determining, by the terminaldevice, a second signal based on second mapping relationship informationand the first signal, wherein the second mapping relationshipinformation comprises: a correspondence between the second signal andthe first signal, and a correspondence between the first signal and atleast one of a third signal, attribute information of first data, andattribute information of second data.
 6. The method according to claim5, wherein the target data is application-layer data, and wherein thedetermining, by the terminal device, the signal structure of the uplinksignal based on the uplink status and the type of target data furthercomprises: determining, by the terminal device based on the firstmapping relationship information and the second mapping relationshipinformation, that the uplink signal comprises: the first signal, thesecond signal, the third signal, and the first data.
 7. The methodaccording to claim 5, wherein the target data is non-application-layerdata, and wherein the determining, by the terminal device, the signalstructure of the uplink signal based on the uplink status and the typeof target data further comprises: determining, by the terminal devicebased on the first mapping relationship information and the secondmapping relationship information, that the uplink signal comprises: thefirst signal, the second signal, and the second data.
 8. The methodaccording to claim 1, wherein the uplink status is an uplinksynchronized state, and the target data is application-layer data, andwherein the determining, by the terminal device, the signal structure ofthe uplink signal based on the uplink status and the type of target datafurther comprises: determining, by the terminal device based on thirdmapping relationship information, that the uplink signal comprises: asecond signal, a third signal, and first data.
 9. The method accordingto claim 8, wherein the third mapping relationship informationcomprises: a correspondence between attribute information of the firstdata, the second signal, and the third signal.
 10. A terminal device fordata transmission, comprising: a processing unit configured to determinea signal structure of an uplink signal based on an uplink status and atype of target data; and a transceiver unit configured to send aselected first signal using the uplink structure of the uplink signalbased on first mapping relationship information and the signal structureof the uplink signal, the selected first signal sent to a network deviceusing a selected one of a plurality of different time-frequencyresources, and the first mapping relationship information indicating tothe network device the signal structure of the uplink signal based on amapping between the selected first signal to the selected time-frequencyresource.
 11. The terminal device according to claim 10, wherein thefirst mapping relationship information comprises: a correspondencebetween the first signal and the signal structure of the uplink signal,and/or a correspondence between a resource used for transmitting thefirst signal and the signal structure of the uplink signal.
 12. Theterminal device according to claim 10, wherein the uplink status is anuplink out-of-synchronization state.
 13. The terminal device accordingto claim 12, wherein the target data is empty, and wherein theprocessing unit is configured to: determine, based on the first mappingrelationship information, that the uplink signal comprises only thefirst signal.
 14. The terminal device according to claim 10, whereinbefore the transceiver unit sends the uplink signal based on the firstmapping relationship information and the signal structure of the uplinksignal, the processing unit is further configured to: determine a secondsignal based on second mapping relationship information and the firstsignal, wherein the second mapping relationship information comprises: acorrespondence between the second signal and the first signal, and acorrespondence between the first signal and at least one of a thirdsignal, attribute information of first data, and attribute informationof second data.
 15. The terminal device according to claim 14, whereinthe target data is application-layer data, and wherein the processingunit is configured to: determine, based on the first mappingrelationship information and the second mapping relationshipinformation, that the uplink signal comprises: the first signal, thesecond signal, the third signal, and the first data.
 16. The terminaldevice according to claim 14, wherein the target data isnon-application-layer data, and wherein the processing unit isconfigured to: determine, based on the first mapping relationshipinformation and the second mapping relationship information, that theuplink signal comprises: the first signal, the second signal, and thesecond data.
 17. The terminal device according to claim 10, wherein theuplink status is an uplink synchronized state, and the target data isapplication-layer data, and wherein the processing unit is configuredto: determine, based on the first mapping relationship information andthe third mapping relationship information, that the uplink signalcomprises: a second signal, a third signal, and first data.
 18. Theterminal device according to claim 17, wherein the third mappingrelationship information comprises: a correspondence between attributeinformation of the first data, the second signal, and the third signal.19. A data transmission method, comprising: detecting, by a networkdevice, a first signal in an uplink signal, the first signal sent by aterminal device using a selected one of a plurality of differenttime-frequency resources; determining, by the network device, a signalstructure of the uplink signal based on a result of detecting the firstsignal and first mapping relationship information indicating to thenetwork device the signal structure of the uplink signal based on amapping between the selected first signal to the selected time-frequencyresource; and receiving, by the network device, the uplink signal basedon the signal structure, and/or responding, by the network device, tothe uplink signal based on the signal structure.
 20. The methodaccording to claim 19, wherein when the network device finds the firstsignal, the determining, by the network device, the signal structure ofthe uplink signal based on the result of detecting the first signalfurther comprises: determining, by the network device, the signalstructure based on the first mapping relationship information and thefirst signal, wherein the first mapping relationship informationcomprises: a correspondence between the first signal and the signalstructure, and/or a correspondence between a resource used fortransmitting the first signal and the signal structure.